Swimming is more efficient for people when swim fins are used and swimming and diving have developed into sports, occupations, and also as a military activity. Devices have been developed through the years to improve the use of swim fins. Swim fins are an effective device for improving a user's speed and power in traveling through the water. Open heeled fins are predominantly used by high end user's within the dive community, and for top level snorkeling and swimming with fins.
One major advantage of the open heeled fin is that it is more adjustable than other fins by the means of a heel strap that usually incorporates the use of one or two buckles to adjust it because the strap is usually not very elastic. Since the strap must withstand serious pressures that might tear about softer more flexible materials when used in a more elastic strap. Open heeled fins are propelled by means of a variety of blade embodiments independent of the heel strap and they allow the user to more easily wear protective foot gear, booties. These booties allow the use of the fins in colder water with booties comprising thicker insulation or in warmer water with thinner booties.
Most of these fins use a boss comprising a boss button and boss post integrally affixed on the outer surface of either side of the foot pocket. The heel strap is generally held in place by a buckling mechanism (or in alternative embodiments stainless steel springs or elastic fibers may be held in place by respective securing plates). Beyond the strap's adjustability, the straps can be replaced if broken to keep the fin in service. Securing devices such as buckles or securing plates can damage the strap, spring or elastic fibers, and can also malfunction or break themselves rendering the fin inoperable.
Many complicated forms of straps, springs, elastic fibers, buckles and securing plates have been developed through the years by many different inventors. Past inventions in the prior art are clearly and substantially disclosed by U.S. Pat. No. 6,923,697 of Wagner. U.S. Pat. No. 6,923,697 of Wagner is the closest prior art to the present invention, and relates directly to open heeled swim fins with a heel strap secured to both sides of the foot pocket, and relates more particularly to orifices cut directly through the strap with end tabs appropriately sized so that they can be uniquely secured within the orifice to form a loop. Said orifices may be secured over the boss button of a fin, but must also be of a substantially solid materially enough so as to not break during normal use and strong enough to withstand the pressure of the tab trying to pull back through the orifice when it is coupled to the orifice to form a loop. The elongation capability in our tests of the straps taught by Wagner allowed the strap to stretch to 134 percent of its original size which is typical for elastomeric straps in which the need to keep the strap from breaking exceeds the need for elasticity in the strap. With limited elongation properties and the desire to couple with the tab, the orifices when small enough to stay under the boss button are difficult to place over the boss button. When the orifices are large enough to easily pass over the boss button, they are then large enough to easily ride back off the boss button during normal use. The device taught by Wagner does not incorporate any of the unique features of the multi-use adjustable bellows-shaped aperture strap, but concentrates on orifices and tabs that can form loops when coupled.
Additionally, other prior art swimming strap structures do not offer adequate elongation properties to allow for the changes in the dimensions of various boss posts and boss buttons. If the buckle, securing plate, or strap with orifices has holes that are too small to pass over the boss button or boss post, the buckle, securing plate or strap may not work properly. If the securing plate, the buckle or orifice taught by Wagner is too large, the strap may come off the boss during normal use, during storage or when the fin is in transit. Under many conditions, this is inconvenient and it is always undesirable. The boss post and boss button have fixed diameters, and if the securing holes for the buckles, securing plates and straps have fixed diameters or diameters with little elongation capabilities, they offer a problem in that they may not match and seat together properly with the boss buttons and boss posts.
Additionally, straps that are used generally in securing the heel, or securing the head of the user or securing the gear of the user, or as an elastic belt for the use must be substantially of a material that will not break under normal use in order to handle the stresses placed on it by normal use in diving and swimming and when on a boat. At present, these stronger materials do not lend themselves to substantial elongation. A strap elongation of 150 percent increase in its elongation size is considered excellent. Typical strap elongations of 135 percent of their original size are normally found. This limited elongation capability limits the effective use of such straps for heel straps, for straps to help hold on goggles, or masks, and for straps that are used for securing gear on the diver, swimmer or on a boat or as an elastic belt for the diver or swimmer.